Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Home Brew?

  1. Dec 13, 2004 #1
    Hi all, I was wonder if any of you have ever tried to brew your own beer, wine, other alcoholic products.

    I look up the Emden-Meyerhof-Parnas reaction scheme in my I chem text book and it looks like a fairly simiple experiment

    Sucrose + yeast + disodium hydrogen phosphate ------> happniess

    is the safe to drink the by products of this reaction, will it produce methanol as a byproduct?

    Thanks for you advice
  2. jcsd
  3. Dec 13, 2004 #2
    I'm not sure what the Na2HPO4 is for... But yes, you can drink it, and no, it doesn't make any MeOH. One thing, though. Sucrose (C12H22O11) is a disaccharide, which is not fermentable. In water, the molecules break up to form fructose and dextrose (C6H12O6), which do ferment. The conversion is facilitated by heat and acidity (Maybe that's what the Na2HPO4 is for; if so, I think I'd use something like citric acid instead. Or use ascorbic acid, which is a nutrient for the yeasties, too). By the way, I've made "hooch" by fermenting apple juice. I would also add ~1cup of sugar per 64oz. to increase the potency...TOO much sugar, though, and it tastes like varnish! Actually, it tastes rather like varnish anyway, but after a glass or so one doesn't especially care...;)
  4. Dec 13, 2004 #3
    So all I need to do is add yeast to apple juice plus a cup of sugar and heat the solution. How hot should I get it? How long? Do I have to worry about keeping to contents O2 free?
  5. Dec 14, 2004 #4


    User Avatar
    Science Advisor
    Gold Member

    Sodium phosphate is needed for energy exchange reactions; in Embden-Meyerhof cycle, some transformations from adenosine diphosphate to adenosine triphosphate by the use of an inorganic phosphate, available from this chemical.
    The contents of the reaction mixture is not to be drunk, they will only be okay for human health after some hygienic treatments are fulfilled.
  6. Dec 14, 2004 #5


    User Avatar
    Staff Emeritus
    Science Advisor
    Gold Member

    Fermentation using apple just is callled hard cider.

    I brew my own beer. You have be carefull you brew. First you want to make sure that you maintain a high santard of sanitation when you brew.

    Second, you do not have to worrie about the oxygen when brewing. In early stage, oxygen is important. Part of the liquid will be anaerobic. Fermentation occurs at room temperature (20C). This is alsmot the yeast optimal temperature. You can also do fermentation at low temperature (10C) for lagers. Temperature is important for flavor development in specific type of beer, wine and other fermented brew. Above 25C, bacteria will start to grow faster than the yeast and contamination will occur.

    For brewing cider, you first you have to heat the appe juices at around 75C for about 20 minutes, you will pasteurize the juice. This will kill 99.99% or more of the bacteria. You need an apple juice that has no conservation agent or any sulphite because these chemicals will interferre with the fermentation by killing your yest. A pasteurize juice is fine. You had the sugar will you are heating the juics but not the sugar you have at home. You need fermentable sugar such as honey, brown sugar, molasses, corn sugar (dextrose), cane sugar and maple syrup. For a cider, honey you be a good sugar to had. It will had some taste.

    You then let you apple juice and sugar mix cool to room temperature. Keep the juice cover, you do not want bacteria to get in. Once you juice is ready, add the yeast. A champagne yeast would be a good choice and can probably be bought at any local homebrew store. You fermentation should occur in well sanitized plastic bucket (FDA approved) or glass carboy. The busket and carboy should be capped as to avoid contamination from the ambiant air but you need an airlock with water to let the CO2 come out (this is also available at you homebrew store). You can check the brewing process but looking at the airlock. If you see a lot of bobble comming out, it is fermenting. No bubble or one bubble every minutes or so, the fermentation is done or if it the second day second you have not see bubble, either you cap is letting air out or you have a problem. You can usually see a thick foam on top of the juice if it is fermenting. Wait for about 7 days and your fermentation should be finished. You either bottle in clean sterile bottles and let it age for at least 2 to 3 weeks or do a secondary fermentation by transferring you cider from the bucket to the a sanitized carboy and let it for another week or so. To have carbonation you need to prime the fermented product (about 1 cup per 23 liter of cider). To do this you had fermentable sugar to the cider just before bottling. You should have a nice carbonation

    For sanitation, there product available. Homebrew store sometime carry sanitized that do not rinsing. I suggested this type. You can also make a 5% bleach solution using home bleach. However, you nee to rinse several time (10 to 20 times) with sterile water. To steilize bottle, you can cook the glass bottle in the oven for 2 hours at 350F. Just don't take the bottle out immediatly, they will break. let the oven cool down first.

    Sanitation is important in homebrewing. Bad sanitation will result in a bad beer and by-product fermentation.

    For beer and wine, there is similar and different process.
    Last edited: Dec 14, 2004
  7. Dec 14, 2004 #6
  8. Dec 14, 2004 #7
    Here's how I've done it. First, I dissolve the sugar in the juice. I then take about 8-12oz of the liquid and heat it to 90-100 deg.F; hot to the touch, but not uncomfortable. Then I add the yeast to that. After about ten minutes, it froths up with bubbles, and I stirr it thoroughly, pour it back into the main container, and shake it up. I then loosen the cap a little, so its got just a slight amount of up-down play. I sit the jug aside (a warm place is best) and wait. One point to remember: foam will accumulate at the top of the bottle in the early stages of fermentation, and it needs to be mixed back into the liquid. Otherwise, it will ooze out the top; not a real problem, but it causes a little loss of the product. With an ambient temperature of ~90 deg.F, the brew should be pretty well fermented in 4-5 days. Lower temp. means a longer wait. Ideally, you should wait until the fermentation stops and the yeast settles on the bottom, leaving a more or less clear liquid. I usually ended up consuming mine well before then, though. The longer it sits, the less varnish-like will be the taste. I've also used other juices, but apple juice seems to ferment the most quickly, and it produces the strongest hooch. By the way, the word "hooch" refers to any homemade booze, usually one that's of "rot-gut" quality...
  9. Dec 14, 2004 #8


    User Avatar
    Staff Emeritus
    Science Advisor
    Gold Member

    Top fermenting yeast do not stay at the top it settle on surfaces and it will settle at low oxygen spots. The wort also has to be well oxygenated. Oxygen will be used completly and you will mostly have the anaerobic fermentation.

    I also had a univeristy level course for Food microbiology and the prof, which made his own beer, wine and cheese, demonstrated that oxygene, not a low level, is requiered for optimun fermentation. If I remember correctly, it is Louis Pasteur that show what a strict anaerobic environment gave sub-optimun fermentation.
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?

Similar Discussions: Home Brew?
  1. Home test for lead (Replies: 36)

  2. Home Made LCD Cleaner? (Replies: 3)